1. Field of the Invention
The present invention relates to a pressure balance valve that is used to adjust a pressure between cold and hot waters automatically to balance a pressure difference.
2. Description of the Prior Art
Referring to FIG. 1, a conventional pressure balance valve 10 includes a body 11, two side covers 12 disposed on two sides thereof to define a chamber 13 with the body 11 individually; a sleeve member 14 fixed in the chamber 13; a valve core 15 fitted into the sleeve member 14 and moves along the sleeve member 14 axially and including a pressure sensing wall 151 secured on a middle section of the valve core 15, a cold-water pressure room 152 and a hot-water pressure room 153 defined in two side thereof respectively so that after cold water from a cold-water inlet 111 of the body 11 and hot water from a hot-water inlet 112 flow through the cold-water pressure room 152 and the hot-water pressure room 153, they further flow out of a cold-water outlet 113 and a hot-water outlet 114 of the body 11. Thereby, a pressure difference generates in the cold-water pressure room 152 and the hot-water pressure room 153, and the valve core 15 moves axially based on a sensed pressure of the pressure sensing wall 151 so that the cold and the hot waters in the cold-water and the hot-water pressure rooms 152, 153 are adjusted to keep a balanced water pressure, thus controlling water temperature exactly.
However, an error value within positive and negative 2 degrees Celsius can not be obtained effectively, causing an unstable water temperature.
It is because a vortex generates in the cold-water pressure room 152 and the hot-water pressure room 153, therefore after the cold and the hot waters flow into the cold-water and the hot water pressure rooms 152, 153 and when the water pressures change, the vortex generates and the valve core 15 does not move stably or does not keep a balanced pressure in a short time.
Even though the valve core 15 obtains a balanced pressure after a long period of time, the cold and the hot waters in the cold-water and the hot-water pressure rooms 152, 153 can not form an enough back pressure, so the valve core 15 does not sense the pressure difference or the pressure change precisely.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.